10 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
This boiler uses LED flash patterns
Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →
The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.
| GC number | Appliance (register name) | Produced |
|---|---|---|
| 41-075-34 | 100/2 HE Plus | 2004–2006 |
Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.
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Your boiler has stopped working because the internal fan used to clear out waste gases is not spinning correctly.
Your boiler has become too hot and has automatically shut down to protect itself.
Your boiler's internal computer has developed a fault and can no longer control the heating process safely.
Your boiler's internal computer has failed and can no longer control the heating process safely.
Your boiler has detected that water isn't moving through the system properly or there isn't enough water inside, causing it to overheat quickly.
Your boiler has stopped working because its internal temperature sensor is reporting an error and needs attention.
Your boiler's internal computer brain has developed a critical fault and is unable to control the heating process safely.
Your boiler has become too hot and has shut down as a safety precaution to prevent damage.
Your boiler has likely overheated because water isn't moving through the system properly, causing the unit to shut down for safety.
Your boiler has stopped working because the internal fan, which safely exhausts gases, is not spinning at the correct speed or has failed completely.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes